Vitamin D as a biomarker of health in snoring children: a familial aggregation study.

BACKGROUND: Hypovitaminosis D is a common health problem. The purpose of this study was to investigate the inter-relationship between serum 25(OH)D levels and paternal and maternal vitamin D status in a sample of snoring children. METHODS: We selected 137 participants for whom serum 25(OH)D had been measured and underwent overnight polysomnography evaluation. Serum glucose, lipids, liver enzymes, parathyroid hormone, insulin, and glycated hemoglobin were also measured. Glucose and insulin levels were used to estimate insulin resistance with the homeostasis model assessment (HOMA-IR). RESULTS: Vitamin D insufficiency (<30 ng/mL) and deficiency (<20 ng/mL) were found in 40.9 and 17.5% of children, respectively. After adjustments for age, BMI z-score and seasonality, the odds ratio for risk of vitamin D insufficiency according to the vitamin D status of parents were: OR (95% CI): paternal insufficiency 15.1 (2.7-35.7), p = 0.002; maternal insufficiency 7.2 (2.4-22), p = 0.001. When children with vitamin D deficiency were analyzed separately, serum 25(OH)D concentration was found to be associated with the apnea-hypopnea index (r = -0.647, p = 0.009) and respiratory arousal index (r = -0.669, p = 0.034). CONCLUSIONS: Family patterns of vitamin D could be helpful for the early identification of children at risk of metabolic and/or sleep disturbances and when considering strategies to improve vitamin D status. IMPACT: Family patterns of vitamin D could be helpful for the early identification of snoring children at risk of metabolic and/or sleep disturbances. Significant associations were found between serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and their parents. An inverse association between 25(OH)D levels and OSA severity was detected in deficient vitamin D children. Children with insufficient and deficient vitamin D status tended to have a worse metabolic profile, so strategies are needed to improve vitamin D status.

Systemic inflammation and sympathetic activation in gestational diabetes mellitus with obstructive sleep apnea.

BACKGROUND: Although some evidence suggests an association between obstructive sleep apnea (OSA) and gestational diabetes mellitus (GDM), its consequences still remain largely unknown. We sought to determine whether OSA is associated with higher inflammation and sympathetic levels in GDM, and to relate them with insulin resistance and perinatal outcomes. METHODS: OSA was identified by polysomnography and defined as an apnea-hypopnea index of ≥ 5 h-1. Plasma cytokines (TNF-α, IL-1ß, IL-6, IL-8, IL-10), metanephrine, and normetanephrine were determined by immunoassays. RESULTS: We included 17 patients with GDM and OSA and 34 without OSA. Women with GDM and OSA had higher normetanephrine concentrations [81 IQR (59-134) vs. 68 (51-81) pg/mL]. No differences in the inflammatory profile were found, while IL-1ß was higher in patients with mean nocturnal oxyhemoglobin saturation ≤ 94%. We found positive correlations between increased sympathetic activation and IL-1ß, with obstructive apneas, while time in REM showed an inverse relationship with IL-1ß and metanephrine. Furthermore, IL-10 was inversely related with time in sleep stages 1-2, and with the arousal index, and it was positively related with time in slow-wave sleep. Significant correlations were also found between IL-1ß and insulin resistance. There were no significant differences in neonatal characteristics; however, we found inverse relationships between IL-10 and birth weight (BW), and percentile of BW. CONCLUSIONS: OSA increased sympathetic activity, and IL-1ß concentration was higher in patients with GDM with lower nocturnal oxygenation, all of which were related with obstructive events, and time in REM. Moreover, IL-1ß was related with insulin resistance, and IL-10 inversely correlated with neonatal BW.

Surfactant protein D concentration in a pediatric population with suspected sleep disorder.

Obstructive sleep apnea (OSA) affects between 2% and 4% in children and there is a search for new biomarkers that can be useful both in the diagnosis and in the evolution of the disease. The surfactant protein D (SP-D) is a collection that is part of the innate immune system exerting an anti-inflammatory and antimicrobial effect. Thus, the objective of this study was to evaluate the concentration of SP-D in the suspect OSA pediatric population. A total of 178 children were recruited in this prospective study. Blood samples, sleep parameters, feeding habits, anthropometric, sociodemographic, and family data were collected. Specific biochemical determinations were made, and the plasmatic concentrations of SP-D were measured by enzyme-linked immunosorbent assay. We found no statistical correlation between the SP-D concentration and the apnea-hypopnea index (AHI) from the data. Nevertheless, the changes in SP-D levels could be correlated to a large extent by the arousals that often go along with hypopneas (r = -0.258, p = 0.011 unadjusted; r = -0.258, p = 0.014 adjusted by age and body mass inded [BMI] Z-score). Intermittent hypoxia was correlated with C-reactive protein levels (r = 0.547, p < 0.001 unadjusted; r = 0.542, p < 0.001 adjusted by age and BMI Z-score). Although AHI and SP-D did not appear to correlate, a secondary analysis suggests that sleep fragmentation, which is produced by arousals, may do, and further research is needed to determine the mechanisms by which changes in SP-D occur in OSA.

Polysomnographic Characteristics of Snoring Children: A Familial Study of Obstructive Sleep Apnea Syndrome.

BACKGROUND AND OBJECTIVES: Available evidence suggests a familial basis for OSA. The aim of the present study was to assess the potential influences of parental OSA in predicting the diagnosis and severity of OSA in snoring children. METHODS: Observational study, we prospectively enrolled 84 children and their parents. A complete nocturnal polysomnography was performed. Children were categorized into 3 severity groups according to the apnea-hypopnea index (AHI<1h-1, AHI≥1h-1 to AHI<5h-1, and AHI≥5h-1). Adults were grouped according two criteria (AHI≥5h-1 and ≥10h-1). RESULTS: There were no significant differences in age, gender, BMI and BMI z-score among groups. Among the children, 54.7% had an AHI≥1h-1 and 21.4% had an AHI≥5h-1. Overall, we observed that 60.7% of fathers and 23.8% of mothers of our population had OSA (AHI≥5h-1). The prevalence of fathers with OSA increases with the children's severity (83% in the group of children with moderate-severe OSA, p=0.035). The odds of having moderate-severe pediatric OSA (AHI≥5h-1) were more than 4 times higher among children with a father with AHI≥5h-1 (OR: 4.92, 95% CI: 1.27-19.06; p=0.021). There was no evidence of any maternal influence on OSA severity among the children studied. CONCLUSIONS: Our findings suggest a high prevalence of OSA among the family members studied with an increased association of childhood OSA with paternal OSA. Prediction of OSA risk among children can be significantly improved by adding data on paternal OSA status.

Prothrombotic state in children with obstructive sleep apnea.

OBJECTIVE: Increased blood coagulation might be one important mechanism linking obstructive sleep apnea (OSA) with cardiovascular diseases. We tested the association between several hemostatic parameters and sleep breathing-related variables in a representative pediatric population with a clinical suspicion of OSA. METHODS: Polysomnography was performed in 152 snoring children to diagnose OSA. Anthropometric and clinical data were registered and venous blood samples were collected for the measurement of platelet count, plateletcrit, platelet distribution width (PDW), mean platelet volume (MPV), prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and C-reactive protein. RESULTS: Children with OSA had significantly higher platelet count, plateletcrit and PDW compared with those without OSA. After controlling for the anthropometric characteristics (age, gender, body mass index (BMI) z-score), platelet count negatively correlated with minimum SaO2 while the plateletcrit correlated with time with SaO2 <90% and MPV correlated with apnea-hypopnea index. PT and PT international normalized ratio correlated with mean SaO2 and aPTT correlated with the oxygen desaturation index. CONCLUSION: Our findings suggest that different OSA-related effects may be factors contributing to an enhanced coagulability in pediatric OSA. Measures reflecting apnea severity and disrupted sleep were associated with clotting factor changes independent of covariates affecting hemostatic function.